Not just scarcity, groundwater contamination is India’s hidden crisis

More than three-quarters of India’s rural population depends on groundwater for drinking, but the country’s aquifers are not only under tremendous stress, the quality of water they provide is also deteriorating.

indiaUpdated: Mar 22, 2017 12:55 IST

Malavika Vyawahare

Hindustan Times

Devotees bathe in Ganga river near Sangam in Allahabad. (AFP File Photo)

More than three-quarters of India’s rural population depends on groundwater for drinking, but the country’s aquifers are not only under tremendous stress, the quality of water they provide is also deteriorating.

Government data says 94% of the population has access to improved water sources but this number does not tell the whole story. If you dig deeper and question the quality of available water, the crisis becomes murkier and more dangerous.

Surface water contamination receives a lot of attention because of the visible pollution of this water. In India, 19 states have reported fluoride contamination of water and groundwater in at least 10 states is contaminated with arsenic.

India has over 30 million groundwater extraction points and barring a handful, in all states a majority of wells have registered declining water levels in the pre-monsoon months over a decade from 2006 to 2015.

“If current trends continue, within 20 years 60% of all aquifers in India will be in a critical condition,” according to a 2012 World Bank report.

Falling groundwater levels are only going to make things worse, according to experts. It can lead to an increase in the concentration of arsenic in water, as the volume of the groundwater in the aquifers falls the same amount of contaminant will exist in higher concentration.

Users are also forced to dig deeper to access groundwater and the likelihood of contamination is higher because these metals are present in higher quantity in the crust as compared to the surface.

The prospect of an arsenic contamination crisis has particularly caught the attention of leaders and experts.

“There is an urgent need to start a nationwide movement to make people aware of the arsenic problem,” Uma Bharti, Union minister for water resources, said at a conference organised earlier this month to look into the issue of arsenic contamination.

She has reason to be worried.

Of the 10 states that have arsenic contamination, 7 - West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam, Manipur and Chhattisgarh - have reported contamination level that is above the permissible limit of 10 micrograms per litre (µg/L.).

Most of these states lie in the Ganga basin, where a large population resides and relies on groundwater not just for irrigation but also for drinking purposes.

Though iron is the biggest groundwater chemical contaminant in India, the number of habitations, or household clusters, affected by this problem have decreased from 151,762 in 2012-13 to 110,111 in 2015-16, according to a WaterAid India analysis.

Iron in water is not known to cause any severe health impacts.

However, the number of habitations affected from arsenic have increased over the years from 3,728 in 2012-13 to 7,535 in 2015-16.

Consumption of arsenic contaminated drinking water can lead to cancer. It can also cause arsenicosis, a condition that is as sinister as it sounds, manifesting as skin lesions, pigmentation changes and an abnormal thickening of the skin.

Excessive fluoride may cause fluorosis that can cause discolouration of teeth or can lead to skeletal deformities. It can also cause damage to neurological, muscular and gastrointestinal systems.